The Jibblies

I'm going to keep this up. Had two tests this week so I was busy with that, but I'm also a lazy butt. But we're pushing on!

[Genesis 15:1-3]
Riding on that cool victory of saving Lot, God decides to give Abram a pep talk, saying "See? See? Told you I'd shield you." God also encourages Abram for not taking the spoils from the jerks who ran the town, assuring Abram that the relationship they have and the promises God gave him are an even better reward than the ones he just passed up.
Abram jumps on this opportunity to go "Yeah cool thanks. About those promises..." and begin to ask God exactly when that whole promise thing was supposed to happen. Abram was obvious concerned as he had been promised that his descendants would form an entire nation, but here he was well past 70 years old with his only current heir being one of his servants that he just happened to like more than others.
Abram demonstrated to us last time with his private militia that it does not violate your relationship or your promise with God when you prepare on your side; in fact, you're expected to prepare on your side. Here he demonstrates that it's not wrong to question what's going on. Abram expected descendants, and victory in saving Lot wasn't extremely fulfilling when the first promise didn't look like it was going to be fulfilled, so he calls God out on it, and that's okay. Compared to some of the stuff David prayed, his questions were quite tame.
We never see God punishing doubts and questions. When you make inquiries for the purpose of learning more, God rewards that. We all have an aversion to people questioning our beliefs, and a sense of guilt comes when we question our own, but plenty of Bible folks weren't afraid to call God out on whether or not He was who He said He was. We freak out over things like Richard Dawkins books, but if people are asking questions we should be able to answer them. When someone refuses to let me even ask questions, I immediately begin they are manipulating me and actually have no idea what they're talking about.

[4-6]
God doesn't really give Abram any new information, but reassures him that he's going to have so many descendants that his head will spin. God later ends up fulfilling this in two different ways: the literal, physical country of Israel is a fulfillment of this promise, as well as the spiritual descendants that would come through future covenants.
A cool bit of text here says that Abram believed God, and God credited him righteousness for it. Righteousness is a tricky subject when it comes to pre-law Bible characters. They did not have the Levitical law, so their righteousness couldn't really be based on whether or not they wore polyester or covered their poop properly. Instead, in the case of Adam and Eve, He bases their righteousness on obedience with what He has told them. In Abram's case, Abram got righteousness credited to his account for his faith. Elsewhere in Scripture the covenant God has with us today is compared to God's covenant with Abram moreso than God's covenant with Moses and Israel, so this is worth paying attention to.
I'm a math major, and I like to see the world as obeying mathematical rules that God Himself laid down. One of those rules deals with equality: if we're dealing with a value and we want to switch it out for another one, we can only do that if the two values have been proven equal. If we don't like one side of an equation, we can't just say "Man, that would be a lot easier to solve without those fractions. I'm gonna switch that side out for the number 6. Done." unless we have proved somewhere that the side in question is equal to six. God could not have exchanged Abram's faith with righteousness unless faith was equal to righteousness. God doesn't cook His books. If He wrote "righteousness" in Abram's ledger, that means that, under the covenant He had with Abram and, by extension, the covenant He has with us, faith and righteousness are the same thing. In Abram's case, it was faith in God's promise for descendants. In our case, it is faith in the finished work of Jesus.

[7-20]
I'm going to be honest: this part is weird and I'm never entirely sure what to do with it.
Basically, Abram asks for proof, so he goes and cuts a goat and a cow in half, and leaves them outside along with a dead bird. He gets tired trying to fight vultures off of them, falls asleep, and gets the jibblies. After the jibblies, God tells Abram that his descendants will be captives in another land for 400 years, but it's cool because God will beat the crap out of the other guys after they get out. Then Abram wakes up and has a vision of an E-Z-Bake Oven and a flashlight moving through the dead animals.
The best explanation I've heard for this is that this mimics a covenantal ritual like the ones every culture seemed to have before we all collectively realized that handshake was a lot easier and a lot less messy. I don't remember the details, but it involves walking between the animal caracasses and getting the blood on their robes. What Abram saw was God manifesting Himself to walk through and sign the covenant for both of them (The only good explanation of the imagery I could find was that the oven was supposed to evoke the future pillar of cloud and the torch the pillar of fire that He would use to lead the Israelites through the desert.) The significant picture here being that God signed for both of them; Abram wasn't even involved. Just another picture of how God's covenant with us is Him coming down here, not us building up to Him.